Point-of-care testing refers generally to medical testing at or near the site of patient care such as in an emergency room. A desired outcome of point-of-care testing is to obtain rapid and accurate lab results to determine a next course of action in patient care. Instruments such as blood gas analyzers and critical care analyzers provide analytical results for a number of different analytes in a relatively short amount of time, e.g., 2 minutes or less. These instruments may employ a disposable sensor assembly having a plurality of different sensors disposed thereon, each for detecting a target analyte in a sample, e.g., a blood sample, flowing thereover or thereby. The sensors may be suitable for the detection and/or quantification of various target analytes for the sample taken from the patient. Exemplary analytes include but are not limited to pH, carbon dioxide partial pressure (pCO2), oxygen partial pressure (pO2), sodium (Na+), potassium (K+), calcium (Ca2+), chloride (Cl−), hematocrit (Hct), hemoglobin (Hb), glucose, lactate, bilirubin, CO-oximetry fractions (fO2Hb, fCO2Hb, fMetHb, fHHb), and the like.
Currently, there is an increasing demand for instruments that provide accurate and precise diagnostic results with reduced sample volumes (e.g., 100 μl or less). Reduced sample volumes are advantageous when limited sample is available from a patient, and in that they may leave further sample for other testing and/or may extend instrument, component, and accessory lifetimes of instruments using the same. Nevertheless, significant work is still needed as precision, accuracy, and consistency remain significant issues with the use of reduced sample volumes in diagnostic testing.